This protocol is a multicenter collaborative trial of Home Infant Apnea Monitors. These devices are used to monitor breathing and heart rate in infants thought to be at risk for SIDS, as well as, normal controls. This study will yield extensive descriptive information regarding the efficacy of apnea monitors, their accuracy, and the ability of these devices to detect clinically important events. In addition to the home monitor, the babies are evaluated with overnight polysomnography and standardized developomental testing. The follow-up of the infants continues until approximately age 1.5 yrs. The GCRC Psychometrist assists with the developmental assessments. Approximately 400-500 patients are screened each year with an average enrollment of 37. A total of 195 subjects have been enrolled to date. Recruitment for the CHIME study ended 2/28/98 and 33 infants at University Hospitals and 14 from MetroHealth are in the 1 year follow-up period.